The present invention relates to automatic package or article sorting conveyors of the general type disclosed in U.S. Pat. Nos. 4,711,341, No. 4,732,259, No. 4,738,347 and No. 4,760,908, the disclosures of which are herein incorporated by reference. Commonly, such conveyors include an endless apron or carrier assembly formed by a pair of parallel spaced endless drive chains connected by longitudinally spaced cross tubes with pairs of tubes slidably supporting package or article transfer pushers. The endless chains are supported by a frame including parallel spaced side frame and cross frame members which also support one or more prelocated crossover networks each including sender, receiver and switch components connected by diagonally extending tracks for shifting the pushers laterally on the cross tubes between the side frame members.
In some applications of such sorting conveyors, it is desirable to operate the conveyor at a relatively high speed, for example, over 400 or 500 feet per minute, without having significant wear on the conveyor components and while minimizing the noise of conveyor operation and the shock or impact on the packages when shifting the packages laterally from the conveyor onto take-away or spur conveyors. The sorting conveyors are constructed with the crossover networks prelocated along the length of the conveyor. That is, prior to construction of the sorting conveyor, a layout is made with the crossover networks located according to the desired location of the spur conveyors. However, if it is desired to change the location of a crossover network or add another crossover network after the sorting conveyor has been installed, for example, to accommodate a new location for a take-away spur conveyor, the sorting conveyor must be substantially modified. This results in considerable expense and down time of the sorting conveyor in order to install a new or relocate a crossover network.